Optical instrument.



No. 872,120., IATENIED NOV. 26, 1907.

J. G. GRAY. OPTICAL INSTRUMENT.

' APPLICATION FILED APR.8,1907.

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A1 1 FlGI WITNE SESI INVENTORI M i/o/m 60/700 @56 5 No. 872,120.PATENTED NOV. 26. 1907.

J. G.- GRAY. OPTICAL INSTRUMENT.

APPLICATION IILED APR.8, 1907.

3 SHBETS-SHEET 2 INVENTORI JOHN 60/?00 6% No. 872,120. PATENTED NOV. 26,1907.

J. G. GRAY. OPTIGAL INSTRUMENT.

APPLICATION FILED APR.8,1907

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JOHN GORDON GRAY, OF PHILADELPHIA, PENNSYLVANIA.

OPTICAL INSTRUMENT.

Specification of Letters Patent.

Patented Nov. 26, 1907.

Application filed April 8. 1907. Serial No. 366,889,

To all whom it may concern:

Be it known that I, JOHN GORDON GRAY, residing at No. 5536 Wayne avenue,Germantown, in the city of Philadelphia, county of Philadelphia, andState of Pennsylvania, have invented certain new and usefulI1nprovements in Optical Instruments, whereof the following is aspecification, reference being had to the accompanying drawings.

My invention relates to that class of instruments in which severaloptical elements are grouped side by side within a containing tube orcasing, and the main purpose of my invention is to afford completeaccess to these elements, for cleaning or other purposes, without thenecessity of removing them from the casing, and moreover, to permittheir removal, when necessary, and their accurate replacement, withoutreference to the fitting of that removable portion of the casing itselfwhich is immediately adjacent to the group.

In the accompanying drawings, Figure I, represents a top or plan view ofthe exterior of a portion. of a telescope tube or casing illustrating myinvention. Fig. II, is a view in side elevation of said portion, thetype of instrument selected for illustration being one provided with theso-called Porro prisms, which are grouped at the region of the offsetshown in Figs. I, and II. Fig. III, is a perspective view of the.removable shell, or portion of the casing which is adjacent to thegroup of optical elements. Fig. IV, is a perspective view of said groupof optical elements and their containing frame, removed from the casing.Fig. V, is a top or plan view of the removable shell, shown in Fig. II.Fig. V1, is a top or plan view of the group of optical elements andtheir frame shown in Fig. IV. Fig. VII, is a transverse section throughthe instrument on a plane indicated by the line VII, VII, in Figs. I,and II, and looking in the direction of the arrows, the plane of sectionbeing such as to indicate, in end elevation, the removable shell and thegroup of optical elements. Fig. VIII, is a transverse, section on theline VIII, VIII, in Figs. I, and II, looking in the direction of thearrows. Fig. IX, is a longitudinal section on the line IX, IX, in Figs.I, and VII. Fig. X, is a plan view of the under side of the group ofoptical elements, showing the removable shell in its relation thereto,but not indicating the adjacent parts of the body.

Referring to the general organization of the instrument, it may bestated that the main tube of the telescope is comprised in two memberswhose axes are out of alinement, but parallel, the said two membersbeing united by means of an offset, within which the group of opticalelements is mounted.

In the drawings, 1, indicates the end region of one of the members ofthe telescope casing, and 2, the end region of the other member, theoffset region being indicated comprehensively at 3. At this offset thecasing comprises a removable shell 4, one end of which has a flange 5,which its closely against a corresponding flange 6, at the proximate endof the member 2, while the other end of the shell fits against theflange 7, formed at the proximate end of the member 1. A longitudinalflange 8, is formed along one edge of the removable shell 4, to permitthe securing thereof by means of screws 10, to the main or integralportion of the offset, while a second longitudinal flange 9, along theopposite edge of the shell permits it to be secured by means of screws11, to a subjacent part 14, which is also removable from the integralportion of the offset. The lower edge 15, of this part 14, fits upon alongitudinal flange 16, formed on the integral portion of the offset.One end of the mem ber 14, is provided with a flange 17, which fitsagainst the flange 6, of the member 2, the other end of the member 14,fitting against the flange 7, of the member 1.

In Fig. III, the member 14, is shown as secured to the shell 4, by meansof the screws 11, the two part shell thus formed being indicated asremoved from the offset. The flange 8, upon the shell 4, is providedwith a downwardly depending rim 20, extending at right angles to theplane of the under-surface of the flange 8, so as to inclose anelongated angular recess 21. The group of optical elements is mounted ina removable frame shown in perspective in Fig. IV. Said frame comprisestwo parallel flat bars 26, and 27,

which are united by means of a ring 28, and c a flattened band 29, bothof which may be cast integrally therewith. The prism 31, is embraced andheld by the band 29, while the prism 30, is embraced as to one portionof its periphery by the ring 28, and as to the remaining port1on by theband, both of which prisms being retained in position by means 40, (seeFigs. III, and V), between which.

line and the flange 5, the exterior surface of the shell may beflattened as indicated at 41. The frame which carries the opticalelements 1s directly secured to the integral port1on of the casing atthe oflset, being thus mounted independently of the shell or removablepart of the casing at that region. This lndependent mounting of theframe is attained as follows :-The bar 26, is provided w th holes 53, toreceive screws which engage w1th the wide flange 16, formed along theedge of the permanent portion of the ofiset 3, at that side. The widthof this flange 16, is 1n excess of the width of the bar 26, so that thelatter may be seated within the lower port1on 15, of the removablemember 14, of the shell. Thus the frame is completely embraced andinclosed by said independently removable member 14, at that side. Thebar 27, is provided with an external project- .ing flange 45, which isadapted to be secured to a flange 18, formed along the edge of thepermanent portion of the casing at the offset, on the side opposite tothe flange 16. Two screw holes 50, and 51, are formed through the flange45, to receive the screws whereby 'it'is directly secured to the flange18; two other holes 46, and 47, being also formed through the flange 45,which register with and permit the free passage of the screws 11, bywhich the flange 8', of the shell 4, is secured to the flange 18, uponthe permanent ortion of the casing. The downwardly epending rim 20, ofthe flange 8, embraces and completely incloses the flange 45, which fitssnugly within the recess 21, of

the shell. If desired, the frame may be provided with pins 58, and59,upon the under side of the bars 26, and 27 respectively, (see Fig. X),which register with corresponding holesformed in the flanges 16, and 18,respectlvely, so as to insure accurate fitting, even though there shouldbe some slight play in the screw holes. A curved recess 60, is

formed in the inner face of the shell portion 14, to receive theproximate part of the band 29, at that region.

In fitting the instrument together, the frame 25, is first secured inposition by means of its independent screws which pass through the holes50, and 51, in the flange 4 5, of the bar 27 and through the holes 53,1n

- the bar 26, thus maintaining the frame and the optical elements intheir proper relation to the optical axes of the members 1, and 2, ofthe casingb'y direct mounting upon the permanent portion of the offsetand without dependence upon the accuracy of fit of the removable shell.The portion 14, of the removable shell is then secured in position bymeans of a screw passing through the hole 65, in its end flange 17,which clamps it against the end flange 6, upon the member 2. The mainbody 4, of theshell is then placed in position with its flange 9,resting upon the upper edge of the member 14, and with its flange 8, anddownwardly depending strip 20, resting upon the upper edge of the flange45, of the frame. The screws 10, 10, are then inserted and pass freelythrough the holes 46, 47, of the flange 45, so as to engage with theflange 18, upon the permanent portion of the offset 3. The screws 11,11, are then inserted and by means thereof the other edge of the shellis secured to the removable part 14.

The screw 63, is then inserted through the hole 64, in the flange 5, soas to secure the main portion of the shell to the flange 6, and finallythe screw 67, is inserted through the flange 7, and engages in the hole68, formed in the proximate end of the shell. It will thus be noted thatthe two parts 4, and 14, comprising the shell can be independentlyremoved, so as to permit access to the optical elements, for the purposeof cleaning, without disturbing the frame in which such elements aremounted.

Where, as in some cases, the optical elements are directly carried bythe removable portion of the casing, it is necessary to construct thefitting surfaces upon said removable portion, and upon the permanentportion of the casing, with great accuracy, in order that the opticalelements may be properly restored to their correct position, after theyhave been removed for cleansing purposes. This is always attended withthe risk of injury to the optical elements, as they may be dropped oraccidentally struck in the handling, and since a notable instance of theuse of such devices is in connection with gun sights, it is desirable toavoid suchexposure under the very disturbing conditions which may exist.By my invention this risk is avoided, and moreover, the necessity forabsolute accuracy in the fitting surfaces is limited to the smallestnumber of parts, none of which need be exposed when it is-necessary.

to clean the optical elements.

I am of course aware that it is not broadly speaking new to construct anoptical instrument with a removable ortion of its shell at ther'egion'of the optica elements, and I am also aware that it is not newto support such elements in the removable portion of the shell itself. Itherefore do not claim such structures.

I claim 1. In a telescope provided with an offset at the region of theoptical elements, the combination with the permanent casing, having anopening limited by flanges parallel to the optical axes; of a frameadapted to carry the optical elements, said frame comrising longitudinalbars which fit upon said anges means for directly securing said bars tosaid flanges; a removable shell adapted to completely inclose said frameand the elements carried thereby; and means for securing said shell tothe permanent portions of said casing independently of the frame.

2. In a telescope provided with an offset at the region of the opticalelements, the combination with the permanent casing having an openinglimited by flanges parallel to the optical axes; of a frame adapted tocarry the optical elements, said frame comprising longitudinal barswhich fit upon said flanges means for directly securing said bars tosaid flanges a removable shell comprising a main portion having adownwardly depending rim adapted to inclose one of said bars and anindependently removable portion adapted to inclose the other ofsaidbars; means for securing the two parts of said shell together and meansfor securing said shell directly to the permanent portion of the casing.

In testimony whereof, I have hereunto signed my name, at Philadelphia,Pennsylvania, this siXth day of April, 1907.

JOHN GORDON GRAY.

IVitnesses.

JAMES H. BELL, E. L. FULLERTON.

